A circuit includes a control inverter, a first latch circuit, and a second latch circuit. The control inverter receives a control signal to generate a reverse control signal. The first latch circuit is activated by the reverse control signal to convert a first input signal ranging from the first supply voltage to the ground into a first output signal ranging from the second supply voltage to the ground. The second latch circuit is activated by the reverse control signal to convert a second input signal ranging from a first supply voltage to the ground into a second output signal ranging from the second supply voltage to the ground. The first supply voltage and the second supply voltage are different.